This invention relates to procedures for making nonwoven pile articles, and more particularly to procedures of the type wherein an adherent backing is applied to the free ends of a pre-assembled array of cut pile yarns or fibers. For convenience of expression, the term "fibers" will be used herein to refer to yarns as well as to individual discrete fibers.
It is known to assemble an array of substantially aligned cut pile fibers having free ends disposed substantially in a common plane, and then to apply an adherent backing to the free ends of the assembled fibers, for production of a nonwoven pile article. Examples of such procedures are described in applicant's U.S. Pat. No. 3,499,807, and in applicant's copending U.S. patent applications Ser. No. 436,640 filed Jan. 25, 1974 (a continuation-in-part of U.S. Ser. No. 229,065 filed Feb. 24, 1972, now abandoned) and Ser. No. 331,658, mentioned above. Pile articles produced in this way may be used as carpets or for other purposes, and offer advantages especially with respect to ease of fabrication and economy of pile fiber consumption.
In procedures of the foregoing character, pile density is controlled or adjusted by performing appropriate operations on the assembled fibers prior to application of the backing. Although the aforementioned patent and applications describe effective ways of achieving such density control, it is found that (as also in more conventionally produced pile articles) spaces may remain between adjacent fiber ends where they join the backing, so that areas of exposed backing may be seen in the produced pile article when the pile fibers are separated. Presence of these exposed areas of the backing is undesirable since they tend to become visible as the pile depth decreases through wear, imparting a threadbare appearance to the article.
Heretofore, complete pile articles comprising a fiber pile adhered or otherwise secured to a backing have sometimes been treated with steam or hot water to alter the physical characteristics of the pile fibers and/or for other purposes. One effect of such treatment is a "blooming" or apparent densification of the free upper portions of the fibers. The blooming effect, however, does not alter the axial spacing of the fibers nor does it extend to the fiber ends which are anchored to the backing; hence it does not overcome the problem of exposure of areas of the backing between fibers and resultant threadbare appearance as the pile wears.